This holiday season, would you consider giving friends and family the skull of a guy who cut off his testicles? We’re dead serious.

With a $200 donation, you can “adopt” one of the 139 specimens in the Hyrtl Skulls collection at the Mütter Museum at the College of Physicians of Philadelphia, which is devoted to medical history. As the number of visitors has grown, vibrations from footsteps have damaged the skulls, causing chipped or broken teeth. Donations support new mounts that absorb these vibrations, plus cleaning and repairs.

The collection, which has been on display for more than 100 years, belonged to Josef Hyrtl (1811-1894), a Viennese physician and professor in the mid-19th century. Anna Dhody, a curator, told TIME that he used the pieces to disprove the science of phrenology, which said that human skull measurements determined intelligence and moral character. The field also contributed to the practice of classifying racial groups by their intellectual abilities and argued white Europeans were the most superior.

So Hyrtl, who believed only God could determine intelligence and personal attributes, sent agents throughout Europe and as far as Egypt and Lebanon to collect predominantly Caucasian skulls and information about the individuals. “What Hyrtl did was show the vast difference in the way these skulls look and how you can’t make sweeping statements about the superiority of one race over another when there is so much difference within the race itself,” Dhody said. Hyrtl’s discoveries cost him his job at the University of Vienna, and he sold the collection.

The Hyrtl exhibit specimens are mostly from people who committed suicide, executed criminals, and almshouse residents because “by law in Europe at that time, if you committed suicide or if you were executed, you and your family had no rights to your remains,” Dhody said.

Here are three skulls that have already been adopted:

Andrejew Sokoloff: This member of Scopzi, the Russian sect that believed in celibacy, died of a self-inflicted removal of the testicles.

Araschtan Gottlieb: This 19-year-old committed suicide by ingesting potassium cyanide because he suspected his mistress was being unfaithful.

Geza Uirmeny: Eighty-year-old reformist herdsman who attempted suicide at 70 by cutting his throat. However, the wound was not fatal because his larynx was ossified, so the cut didn’t go through. The catalog says he lived 10 more years “without melancholy.”

Mütter Museum

Constantin Jacic

Mütter Museum

Izzet Methem Fakhr

And here are three skulls that may still be up for grabs:

Constantin Jacic:Twenty-four-year-old “Serb” robber and murderer who was executed by hanging.

Bartolomeo Pizzocane: Eighteen-year-old bargeman from Sicily who died of tumor albus (tuberculosis of the bone or joint).